Answer:
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Definition: 1 Mark
Explanation: 2 Marks
Sewage is a liquid waste released by homes, industries, hospitals, offices and other users. It also includes rainwater that has run down the street during a storm or heavy rain.
Sewage water contains harmful substances. It is a complex mixture, containing suspended solids, organic and inorganic impurities, nutrients, saprotrophic and disease-causing bacteria and other microbes. So, if the untreated sewage is discharged into rivers and seas, it will pollute the water resources, affect aquatic life. The contaminants of sewage degenerate the water quality to such an extent that they become the home for dreaded diseases like cholera, typhoid, polio, meningitis. malaria and dengue.